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Brilliant_brown [7]

3 years ago

14

If a building is 1,065 feet tall. Starting from a height of 60 feet , windows 15 feet tall are used on the outside of the buildi

ng. How many windows are in one column to the top of the building.

1 answer:

sleet_krkn [62]3 years ago

7 0

1,065 - 60 = 1,005

1,005 / 15 = 67 windows

60ft is 4 windows

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Hunter-Best [27]

10/3 or 3 1/3
is the answer

7 0

3 years ago

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The ages of a random sample of five university professors are 39, 54, 61, 72, and 59. Using this information, find a 99% confide

blsea [12.9K]

Answer:

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

Step-by-step explanation:

Data given and notation

34,59,61,71,59

We can calculate the sample standard deviation with the following formula:

$s^2= \frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$s= \sqrt{s^2}$

s=12.021 represent the sample standard deviation

$\bar x$ represent the sample mean

n=5 the sample size

Confidence=99% or 0.99

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=5-1=4$

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical values.

The excel commands would be: "=CHISQ.INV(0.005,4)" "=CHISQ.INV(1-0.005,4)". so for this case the critical values are:

$\chi^2_{\alpha/2}=14.860$

$\chi^2_{1- \alpha/2}=0.207$

And replacing into the formula for the interval we got:

$\frac{(4)(12.021)^2}{14.860} \leq \sigma^2 \leq \frac{(4)(12.021)^2}{0.207}$

$38.898 \leq \sigma^2 \leq 2792.356$

Now we just take square root on both sides of the interval and we got:

$6.237 \leq \sigma \leq 52.843$

3 0

3 years ago

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Stefan is making new cushion covers for a chair. There are three sizes of cushions on the chair. What is the surface area of the

Valentin [98]

Answer:

990 square inches:)!

Step-by-step explanation:

i took the test >:).

8 0

3 years ago

I WILL GIVE BRAINLY!!! PLEASE ANSWER!

irina1246 [14]

Answer:

its A

Step-by-step explanation:

a translation up would just be it moving

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4 0

2 years ago

Find the inverse for 43 modulo 660

Tatiana [17]

We're looking for $x$ such that

$43x\equiv1\mod{660}$

so for some integer $n$ we can write

$43x+660n=1$

Apply Euclid's algorithm:

$660=43(15)+15$
$43=15(2)+13$
$15=13(1)+2$
$13=2(6)+1$
$\implies(660,43)=(43,15)=(15,13)=(13,2)=1$

From this we have

$1=13-2(6)$
$\implies1=-6(15)+7(13)$
$\implies1=-20(15)+7(43)$
$\implies1=-20(660)+307(43)$
$\implies(-20(660)+307(43))\equiv307(43)\equiv1\mod{660}$

which means 307 is the inverse of 43 modulo 660.

3 0

4 years ago